If my hair type is 4b, is there any products to change my hair type to like 3c?
I hate to burst your bubble, but despite an onslaught of marketing claims, there is no magical product, potion or elixir that can transform your coils and kinks into 3c spirals. You've got to start understanding and appreciating the unique properties of the hair you've got on your head. From your username, I'm going to assume that you're newly natural. Congratulations on making the leap. This is where the hard part begins, and the first step is learning about YOUR hair, not some idealized version of textured hair that you were hoping for. Let me just say, I've been there. Shoot, when I big (little) chopped back in the day, I was hoping for big ringlets like Cree Summer. That was so not what my hair looked like. I learned to appreciate every curl and coil on my head, as I mastered caring for my strands. If you really wanted an elongated look, play around with your texture using twist outs, braid outs and curly rod sets. But, I suggest started to make peace and love with your texture first. Good luck.